May, 2004. Homeward bound from teaching in New York state, I'm driving west from Chicago on Interstate 80, passing stubble fields, white farmhouses, little round-topped silos, and the mounded, freshly leafed-out crowns of hardwood forest between the farms. La Salle, Rock Island, the Mississippi River -- no, the West doesn't begin here -- and into Iowa as a slight roll comes to the green land. There's a muddy stockyard full of cows near Iowa City, the prairie patched with fields and pastures, and fewer trees now -- clumps, singles, strands along fencerows and small rivers. Toward Council Bluffs the land takes longer swells, and I'm crossing the Missouri -- no, not here either -- under a lowering, gray-plate sky, storm warnings breaking into the radio talk show, new corn a few inches high in the moist fields.

In Nebraska, the speed limit jumps to 75, a sure sign of westering. Near Lincoln the fields stretch out plainsier now, and closing in on Grand Island, in bright sun, the Midwestern roll is gone from the land and big-wheeled sprinklers shine in the fields, ready to boost the summer rainfall that won't be enough. So here, maybe? But now I-80 falls in with the Platte River, its braided channels lush with forest. The names are Western now -- Pioneer Village Motel, Stagecoach Restaurant -- and three or four miles short of Kearney, the earth is dry enough for a scatter of pines. Under the Great Platte River Archway Monument that spans the freeway -- definitely not here -- I'm cruising at 80, a windmill spinning hard to my left, a tractor throwing up clouds of dust, neat-rolled hay bales spotting the sprawling fields. Irrigation equipment is everywhere, for corn and hay. I ride the Plains neck and neck with a Union Pacific freight train, off to my right -- if we're not in the West, we're mighty close -- and then, a few miles past Gothenburg, under flat-bottomed cumuli in a vastness of sky, to the southwest there's a low, solitary ridge specked with junipers.

Here.

There won't be another cornfield. There will be cattle in pastures and feedlots, the bumpy fringe of the Sand Hills to the north, ranch houses with windbreaks of tall poplars, outcrops of volcanic rock, power line towers marching into the distance, a few oil rigs bowing and rising, and settlements of doublewides with sheds, old vehicles and assorted machinery. The first glimpse of the Rocky Mountains will come just over the Wyoming border, but by then, in my book, I'll have been in the West for 200 miles.

The West began for me in 1966 when I was 18, driving Route 66 in a very loud jeep across Oklahoma and the Texas Panhandle into New Mexico. The flat expanses looked naked and glary to my East Coast eyes, but the land was wide open and so was my spirit. I passed the miles bellowing the lyrics of  "Mr. Tambourine Man," trying to out-shout the Jeep. My brother, at George Air Force Base in the Mojave Desert, had taken a shine to that country of Joshua trees and creosote bush, but to me, then, it looked only parched and desolate. I was happier with the California coast -- Big Sur, San Francisco, the misty redwoods, and finally western Oregon, where I would conduct my brief career as a college student. It rained all winter and stayed green. The trees were enormous and so were the mountains, the seaside rocky and stormy and fine. Even the wet earth smelled sweet. I began to suspect I'd been born on the wrong coast.

Forty-four years later I'm still here, about as far west as I could settle, but not in the West. Theodore Roosevelt once remarked that California, seaward of the Sierra Nevada, is actually west of the West, and I agree. This sundown fringe of the continent, from southeast Alaska down through the oak-strewn hills of the California coast, is its own region -- a country of earthquakes and volcanoes, dramatic coastline, badly abridged versions of once-profuse rainforests and salmon-thronged rivers, and a half-dozen of North America's great cities with their proliferating suburbs. It is geographically, geologically, climatically, biotically, and culturally distinct from the broad, drier interior region it borders.

In the 1970s I moved to Klamath Falls, Ore., for a railroad job, pursuing my dropout curriculum of drink, self-doubt and confusion, and was shocked to discover that the eastern two-thirds of Oregon was not verdant with Douglas firs and mossy-rock streams. It was Nevada north -- semiarid plateau country of sagebrush and juniper expanses, buttes and cinder cones, clumps of conifered mountains. But the landscape grew on me. I found that I liked the breathing room, the drama of visible distance, and I liked it that the land presented itself in particulars. Not the enveloping hardwood forest of the East, not western Oregon's thick stands of conifers, but this twisted juniper with a packrat nest at its base. This angling ponderosa pine, its orange bark scored with a lightning scar. This huddle of aspens around a spring, and in the distance a few small buttes alive with the slow-moving shadows of clouds.